Electrical switching devices



ELECTRICALv swircrnNG DEVICES Stanley F. Newman, Troy, and Sanford H.Baker, Oak

ThisA invention relates to' electrical switching devices, and moreparticularly t the type of switching device that utilizes magneticfields to produce switch actuation.

Magnetically operated switches, such as the well known reed switch, are,generally mounted within -a 4support that atiords the desired fluxpaths. This support in the past has been made of rather expensivemagnetic material because it was required that thematerial havesubstantially rectangular hysteresis characteristics. This gave th'e'twodistinct remanent states needed for the desired on and ofi switchingaction. problem. lSince large voltage variations could not betolerated,`bias was generally required, and response time was tool largefor many applications.

It is now proposed to overcome these problems by providing a novelswitching device that employs inexpensive magnetic material forachieving efficient magnetic actuav tionof the switching device; Morespecifically, the invention. contemplates a switching device utilizingplural tluxpaths having a common branch, which is aligned with amagnetically operatedr switch. By the -invention the magnetic impedanceof the common branch is `altered so as to cause flux to flow through themagnetic switch when it is desired to establish one switch condition andto bypass the magnetic switch whenanother switchcondition is wanted.With the proposed unique device large voltage variations can betolerated, response time is a minimum, and bias is not an essential. lThe foregoing and other objects and advantages of the invention willbecome apparent from the lfollowing` description and-the accompanyingdrawings, in which:A

FIGURE 1 is a-.perspective view of a switching device incorporating'theprinciples of the invention;v

FIGURES 2 and 3 are schematic diagrams oi the FIG- URE l switchingdevice, illustrating the ilux flow paths; FIGURES 4 and 5 showschematically OR and NOT switches, respectively; andy 4FIGURE 6 is agraph showing thehysteresis characteristics of the material used withthe FIGURE 1 switch.

Referring now to the drawings in detail and initially to FIGURE 1, theillustrated switching device employs a reed switch, denoted generallybythe numeral 10, and may be of any commercially vavailable type,comprising a glass envelope 12 in which is inserted a pair 'ofoyerlapping switch contacts 14 and 16. The switch contacts 14 and 16 areformed of any lsuitable magnetic material of relatively-highconductivity and are connected into a circuit, not shown, which is'to becontrolled. Of course, when the switch contacts 14 and` 16 are engagedor disengaged the Icircuit is respectively closed and opened. Thecondition of the reed switch is determined by the structure designatedgenerally by the numeraly 18 and its magnetic state, as will4 becomemore apparent.' l

The structure 18v comprises a lsupport member 20 formed -with upper andlower plates 22 and 24 held together in any suitable manner by outerrods A26 and 28 and 4an intermediate rod 30. The reed switch 10 ismounted between the upper and lower plates 22 and 24 in any convenientway and in the proximity of the intermediate rod 30, for reasons to" beexplained. The outer rods 26 and 28 lhave wound thereon control windings32 andv United States Patent f O Moreover, calibration presented a s Y,3,256,404 Patented June 14, 1966 tee selectively energized by currentsources, not shown, in a sequence also to he described. The supportmember 20, including the upper and lower plates 22 and 24 and three rods26, 28 and 30, may be made of an inexpensive material that is easilymagnetized vand dcmagnetized, e.g., cold rolled steel or soft iron. Thehysteresis characteristics of cold rolled steel Vare generally shownbythe FIGURE 6 hysteresis loop. The cross-sections of the rods 26, 28and 30 may, by way of example only, be a circle or a polygon. Tounderstand the operation of the FIGURE l switch ing device, Vreferenceis now made to FIGURES 2, 3 and 6. Considering first FIGURE 2, it isassumed that thc control winding 34 is energized and the control winding32'is deenergized. Consequently, the fluxgenerated by the magnetic fieldfrom the control winding 34 will flow in the direction of the arrowwith, for example and without limitation, half of the flux going throughthe intermediate rod 30, 'which constitutes an auxiliary path, andtheother half through the outcrrod 26, which represents the main path. Thedisposition of the reed switch 10 relative to the intermediate rod andthe amount of ilux flowing in the intermediate rod 30 is selected sothat the reed switch `mediate rod 30 becomes maximum since thesaturation llevel of the rod 30 has been approached. This increasedresistance to flux flow will cause the excessive ux to take the easierpath through the reed switch 104 and cause it to 'assume its closcdcondition. Of course, the position of the reed switch 10 relative to theintermediate rod 30 must be selected so as to afford this shunt path.When either or both ofthe control windings 32 and 34 are det energized,the'magnctic impedance ofthe intermediate rod 3Q will reduce, and theflux will no longervbe shunted through the reed switch 10 such that thereed switch 10 will return to its' open condition.

This FIGURE 1 switching device does not require a bias to be operative.Also, in practice this FIGURE 1 device affords a quick response, lessthan .003 second. Furthermore,` the switching device has many uses,particularly in logic circuits, e.g., as shown in FIGURES 4 and 5. y

As modified in FIGURE 4, the switching device is serving as an OR switchand employs the main support member 20 and the reed switch 10 of theFIGURE I device. The outside rod 28 has a single bias winding 36 woundthereon while the rod 26 has two control windings `38 and 40. The biaswinding 36, for the switching device to serve its OR function, must becontinuously energizes so that the flux 'path in the support member 20will be as illustrated in FIGURE 2 and the reed switch 10 will be in itsviewed open condition. Thereafter, by energizing either the controlwinding 38 or the control winding 40 the state illustrated in FIGURE 3will be established due to the reed switch 10 performing as a shunt forthe excess flux. Hence, the reed switch 10 will assume its closedcondition and afford the OR function.

In the FIGURE 5 switching device, which serves as a NOT switch, the samebasic structure of the FIGURE 1 34, respectively. These control windings32 and 34 are switching device can'again be employed including thesupport `member 20 and the reed switch 10. The outer rod'28 will havewound thereon a bias winding 42 and the outer rod 26 both a bias winding44 and a control winding 46. When both bias windings 42 and 44 arewinding 44. vThis can be done, e.g., by the proper direction of windingof the control vwinding 46 or by choosing the correct polarities. rIfhis'cancellation or nulling of the ux will return the switching device tothe FIGURE 2 status since only the flux from the bias winding 42 will beetective. c 4

From the foregoing it will be appreciated that the unique switchingdevice contemplates the use of very inexpensivelmagnetic materials.'Such are not desirableto the operation, for distinct remanent states areof no concern to the on and off switching action. This, in itself,affords a substantial savings. Moreover, the action is quite positiveand quick. Also, as can be appreciated not altered the etiiciency-of thedevice.. Additionally, this switching device by its basic arrangement issusceptible to many diverseuses as logic circuits, two of which havebeen mentioned.l Others will occur to those skilled in the art, eg., asan exclusive OR switch or even as a memory. By combining two or more ofthese switching devices, even more logic circuit combinations can bedeveloped. Also, any oneof these switching devices may have more thanone reed switch and thereby permit multiple circuits to be operated. l

The invention 'is to be limitedjonly bythe'following claims.

What is claimed is:

1l A switching device comprising a magnetically responsive switch havingplural operating conditions and means determining the operatingcondition of the switch, the determining means including a -member ofmagnetic material, the member being so shaped as to provide both aclosed magnetic circuit and a shunt path lfor a part of the total uxowin the magnetic circuit, the shunt path approaching magneticsaturation with a predetermined tiux o'w therethrough, the switch beingin close proximity to the shunt path so that fiui: flow is also throughthe switch when the shunt path' has the predetermined ux owtherethrough, the switch assuming one of the plural operating conditionswhen the tlux ow is therethrough, and energizing means coupled tothemember for altering the ux flow'in the magnetic circuit andaccordingly the shunt'path so as to establish the 'different plural'operating conditions for the switch'.

2. A switching device comprising amagnetically responsive reed switchand means determining the condition of the switch, the determining meansincluding a member of magnetic material, the member being so shaped asto provide both a closed magnetic circuit and a shunt path fora part ofthe total ilux iiow Iin the magnetic circuit, the shunt path approachingmagnetic saturation with a predetermined uX flow therethrough, the reedswitch being in c lose proximity to the shunt path so Ithat ux ow isalso through the reed switch when the shunt path has the predeterminedlinx flow therethrough, means generating a flux in the magnetic circuitso as to establish one condition ofthe reed switch, and means coupled toythe memberfor increasing the flux dow through the shunt path so thatthe flux now is through the reed switch to thereby establish anothercondition of the reedvswitch.

3A switching device comprising a magnetically responsive reed switch andmeans determining the conditioning of the reed switch, the determiningmeans including a member of magnetic material, the member being soshaped as to provide both a closed magnetic circuit and a shunt path fora part of the total ux ilow in the magnetic circuit, the shunt pathapproaching magnetic saturation with a predetermined tiux owtherethrough, the reed lswitch being in close proximity to the shuntpath so that flux ow `is Ialso through the reed switch when the shuntpath has the predetermined tlux flow therethrough, and means generatingfiuxes in thev magnetic circuit so as to establish the diterentoperating conditions of thev reed switch, the generating means includingmeans coupled to the member for increasing the flux ow through the shuntpath s'o that the ux tlow is also through the reed switch and the reedswitch is caused to change from one condition to another.

y 4.A switching device comprising a magnetically responsive reed switchand means determining the condition of the switch, the determining meansincluding a member -ot magneticmateral, the member being so shaped as toprovide'a pair of magnetic circuits having a common branch, the switchbeing arranged in close proximity to the member and also to the commonbranch so as to be responsive to the 'flux ow in the common branch andthereby influenced by the amount of ux flowing therethrough, and meansgenerating different uxes in the circuits so that the magnitude of theflux flow through the common branch will vary and thereby establishdifferent operating conditions for the switch. a

5. A switching device comprising a magnetically responsive .reed switchand means determining the condition of the switch, the determining meansincluding a member of magnetic material, the member being so shaped asto provide a pair of magnetic circuits having a common branch, theswitch being arranged in close proximity'tothe member and also to thecommon 'branch so as to be responsive to the ux ow in the common branchand thereby inuenced by the amount of tiux owing therethrough, meansgenerating a tlux -in the circuits such that the tlow through the commonbranch will produce the unsaturated state thereof and thereby establishone condition of the switch, and means generating another ux in thepaths such that the now through the common branch will produce thesaturationstate thereof and a leakage llux will proceed through theswitch to thereby establish another condition of the switch.

6. A switching device comprising a magnetically responsive reed switchand means determining the condition of the switch, the determining means.including a member of magnetic material having a pair of continuous uxpaths provided with a common branch, the switch arranged in closeproximity to the member and also to the common branch so as to beresponsive to the flux iiow in the common branch and thereby inuenced bythe amount of tlux owing therethrough, means generating a flux in thepaths such that the magnitude of the u'x ow through the common branchwill be of a predetermined level and thereby establish one condition ofthe switch, and means increasing the flux flow through the common branchfrom the predetermined level untilV the resistance to ux ow therethroughis sufficient to cause the fiux to flow through the reed switch andthereby establish another condition of the switch,

7. A switching device comprising a magnetically responsive reed switchand means determining the condition of the switch, the determining meansincluding a member of magnetic material having a pair of continuous tiuxpaths therein provided with a common branch, the reed switch arranged inclose proximity to the member and also to the common branch so as to beresponsive to the flux ow in the common branch and thereby inuenced bythe amount of ilux iiowing therethrough,'a plurality of inductivewindings coupled to the member, and means selectively energizing theplurality of windings so as to generate different ux flows in the pathsand thereby alter the magnetic impedance of the common branch andaccordingly the condition of the reed switch.

8. A switching device comprising a magnetically re-v sponsive reedswitch and means determining the condition of the switch, thedetermining means including a member of magnetic material having a pairof continuous flux pathstherein provided with a common branch, the reedswitch arranged in close proximity to' the' member and l also to the.common branch so as to be responsive to the nux ow in the common vbranchand thereby inuenced by ,the amountof ilux owingtherethrough,.a'plurality of -inductive windings, one of the .inductivewindings being so coupled to the member `as tocontrol the iux in one of'the pair of paths and. another-oftthe windings being so coupled to themember as to control the Vflux in the other. of the pair of paths, andmeans selectively energizing the plurality of windings so that duringoneistate of operation the 'ux fiow through the common branch will be apredetermined maximum and thereby cause the flux flow also to be throughthe reed switch to establish one condition of the reed switch'and duringanother state of operation the ux'ow through the common branch will be apredetermined minimum thereby shunting the reedA switchtoestablishanother condition of the switch.

9. A switching device .comprising a magnetically rcsponsive reed switchand means determining the condition of. the .reed switch, thedetermining means including a.

member of magnetic material having a pair of continuous flux pathstherein each provided with a common branch, the switch being coupled tothe member in close proximity to the common branch so as to beresponsivexto the u-x ow inthe common branch and thereby inuenced by.

the amount of ux owing therethrough, a plurality of inductive windings,one of` the windings being so coupled to the member as to control theuxflow through one of the paths and another of the windings being socoupled so coupled to the member as to contol ux'ow in one path and apair of windings each being so coupled to the memberfasto control ux owin the other path, means selectively energizing the plurality ofwindings so that when the one winding is energized the flux flow throughf the common branch will be a predetermined 4minimum therebyestablishing an open condition'of the reed switch and when either of thepair of windings is energized the ux flow. through the common branchwill be a predeter-` mned` maximum thereby causing some of the'ux ow tonow alsothrough the reed switch and produce the closed condition of thereed switch. n

11. A switching device comprising a magnetically responsiveA reed switchand means determining the condition of the reed switch, the determiningmeans including a member of magnetic material having a pair of continu-.ous'iiux paths therein provided witha common branch,

. winding and the control winding also being coupled to the member so asto be in opposed relation, and means selectively energizingthe pluralityof windingsso that when the bias winding in each path is energized theflux now through the common branch will be a predetermined to the`member as to control the flux ow through the v other path, meansselectively energizing the`plurality of windings so `that with one ofthe windings energized the iiux ow through the common'branch is apredetermined minimum suchthat the ux ow bypasses the reed switchthereby causing the switch to be open and so` that when both windingsare energized the yux ow through the common branch lis 'a`predetermined'maximum such that the ux flow is also through thel reedswitch thereby clos ing the switch. f

10. A switching device comprisinga magnetically `re` sponsive reedswitch and means determining the condition of the switch, thedetermining means including a member of magnetic material lhaving a pairof cotltirlu'ous flux paths therein provided with a common branch, thereed switch being coupled to the member in'close proximity to thecommonbranch so as to be responsive to the iiux flow in thecommon,branchl and thereby influenced by -the `amount of nux flowingtherethrough, a plurality of inductive windings, one of the pluraltyofwindings being maximum thereby producing a certain magnetic impedance tofurther uxiiow and causing the excess flux to fiow through the reedswitch and establish a closed condition thereof and when the controlwinding is also energized the ilux from the other bias winding will benulled thereby causing the ux ow through the common branch 'to be apredetermined minimum and establsh an open.

condition for the reed switch.

' References Cited bythe Examiner UNITED STATES PATENTS 1,897,045 2/1933Fry t 3171ss x 2,962,557 11/1960 Reek 20o- 87 3,037,085 s/1962 Lowry20o-87 x 3,134,908 5/1964 Euwood 317-188 x BERNARD A. GILHEANY, PrimaryExaminer.

ROBERT K. SCHAEFER, Examiner.

D. MACBLAIN, Assistant Examiner.

7. A SWITCHING DEVICE COMPRISING A MAGNETICALLY RESPONSIVE REED SWITCHAND MEANS DETERMINING THE CONDITION OF THE SWITCH, THE DETERMINING MEANSINCLUDING A MEMBER OF MAGNETIC MATERIAL HAVING A PAIR OF CONTINUOUS FLUXPATHS THEREIN PROVIDED WITH A COMMON BRANCH, THE REED SWITCH ARRANGED INCLOSE PROXIMITY TO THE MEMBER AND ALSO TO THE COMMON BRANCH SO AS TO BERESPONSIVE TO THE FLUX FLOW IN THE COMMON BRANCH AND THEREBY INFLUENCEDBY THE AMOUNT OF FLUX FLOWING THERETHROUGH, A PLURALITY OF INDUCTIVEWINDINGS COUPLED TO THE MEMBER, AND MEANS SELECTIVELY ENERGIZING THEPLURALITY OF WINDINGS SO S TO GENERATE DIFFERENT FLUX FLOWS IN THE PATHSAND THEREBY ALTER THE MAGNETIC IMPEDANCE OF THE COMMON BRANCH ANDACCORDINGLY THE CONDITION OF THE REED SWITCH.